Unit 2: Molecules Flashcards by ST Nath (DJ) Lertritwittaya

What are the SI Units Prefixes?

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Explain why carbon is the most suited for being the backbone of everything

Carbon:
- Since it has 4 valence electrons, It can form 4 single bonds and is thus suited for being the backbone due to its stability
- It allows carbs, lipids, proteins, and nucleic acids to form

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What is a monomer and polymer + in the context of carbohydrates?

Monomer:
- Molecules that join to other similar molecules to form a polymer OR one unit of something
EX: DNA’s monomers are nucleotides + Polymer = DNA
Carbohydrates:
- Their monomers are monosaccharides + polymer = carbs

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How are polypeptides formed?

Process:
- Polypeptides are made via condensation reactions which release a water molecule
- The OH/hydroxyl group is from both of the monosaccharide leaves. Leaving the molecule w one oxygen between them
- Bonds are usually formed between 1 and 4 prime carbon of diff. monosaccharides

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What is a monosaccharide

Monosaccharides:
- Defined as a single sugar molecule
- Atoms C,H,O are always in a 1:2:1 ratio EX: C6H12O6
- hydrogen to oxygen ratio is 2:1

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Carbohydrates are also broken down in digestion. What is the process?

Carbs:
- are broken via hydrolysis reactions
- Are defined by an addition of water to split apart the bond of a large molecule

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How are carbohydrates classified?

Classification:
- is classified based on the # of sugar molecules
- one sugar are called monosaccharide, two are disaccharides, and many are polysaccharides + poly are the energy for organisms

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Define hexose sugars and pentose sugars

Hexose:
- are monosaccharides with 6 carbon
EX: Glucose, galactose, fructose
Pentose:
- monosaccharide w 5 carbons
EX: deoxyribose and ribose

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What are alpha and beta glucose and its differences

Glucose:
- are types of glucose and hexose sugars
- alpha: at the one prime carbon, the hydroxyl group is pointed up
-Beta: at the one prime carbon, the hydroxyl group is going down

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Outline 3 properties of glucosej

Glucose:
1. is Soluble in water because it’s polar and can be dissolved in a polar solvent such as water
2. can be easily transported EX: in the bloodstream
3. relatively stable compound and doesn’t degrade as its being transported cause strong cov bonds 4. Yields a great amount of energy when the covalent bonds break

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What are the energy sources in plants and it’s structure

Starch:
- Starch is made of amylose amylopectin
- Amylose: long chains of alpha glucose molecules
- Amylopectin: long chains of alpha glucose + branching of alpha glucose
- Starch is not soluble in water due to the size which allows for compact storage of starch grains w out affecting osmotic pressure
- After 20 glucose units, amylopectin has a branch
- They are bonded w glycosidic bonds
- are compact due to branching and coiling
Note: Starch is made of glucose molecules

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What is the energy source for animals:?

Glycogen:
- is defined as a polysaccharide for short-term energy
- has cov bonds between 1 + 4 carbon and has branches of alpha glucose bonding to 6 prime carbon
- Its insoluble, and compact due to branches and coiling
Note: Glycogen is made of glucose molecules

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What is the polysaccharide found in the cell wall of plants?

Cell wall:
- cellulose has long chains of beta glucose molecules which are unbranched
- molecules bonded between 1 + 4 carbon
- every second beta glucose molecule is flipped resulting in a straight chain
- Cellulose forms groups called microfibrils held together by hydrogen bonds
- Microfibrils have high tensile strength to maintain the structural integrity of cell wall

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What are the different types of fatty acids and their composition?

Fatty acids:
- Contain a carboxyl group (-COOH) and a methyl group (-CH3)
- can be saturated: only contains single bonds between hydrocarbon chain
- can be unsaturated which means they have double bonds that are bent and are called kinks
- Amongst unsaturated, it can be monounsaturated or polyunsaturated meaning one or many double bonds

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How does carbohydrate assist with membrane proteins ?

Mem proteins:
- glycoproteins have a carbohydrate chain
- the carb has a specific shape that can act as an antigen: the molecule that binds to a receptor on a cell surface for cell to cell communication (ID card)

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Outline the roles of glycoproteins

Glycoproteins:
- cell to cell adhesion: interact with other glycoproteins to form tissue
- receptors: when hormones bind = changes metabolism in cell
- cell-cell communication: neurotransmitters bind to glycoproteins
- immune response: act as markers on cells allowing the immune system to distinguish outside cells
- act as an antigen which simulates an immune response = production of antibodies to remove pathogens

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Outline the differences in fats and oils

Fats:
- fats are triglycerides which are solid at room temperature
- they have a higher MP and are usually saturated
- used by animals
Oils:
- oils are triglycerides that are liquid at room temperature w a lower MP
- fatty acids are unsaturated because the kinks mean they are more spread out so they turn liquid
- Oils are used by plants and fish

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Outline the composition of triglycerides and phospholipids

Triglycerides:
- made of one glycerol molecule (a sugar) and 3 fatty acids

Phospholipids:
- made of one glycerol molecule + 2 fatty acids + one phosphate

both are formed via condensation reactions

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Explain how triglycerides are good insulators

triglycerides are good insulators cause they have a low thermal conductivity

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Outline the composition of steroids + whether they can diffuse across cell mem + examples

Steroids:
- they are lipids with 4 carbon rings +. a hydrocarbon chain
- They can diffuse through the cell mem cause they dissolve in fatty acid tail
EX: Oestradiol and testosterone

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Outline the properties of water + give some examples of whr water can be found

Water:
- is polar, covalent, w weak charges at poles
- is dense as a liquid than a solid EX: ice floats in water
- can bond with 4 other water molecules

Examples:
- water makes up the cyto and is also found between cells as interstitail fluid because metabolic processes work best in an aqueous environment

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What is electronegativity + explain why water is polar

Electronegativity:
- the strength of attraction between an atom and its valence electrons

Water:
- oxygen has a more positive nucleus than hydrogen atoms and has greater attraction for the elctrons
- So electrons are shared unequally
- the hydrogen bonds of water are weak

Explain why water is a good solvent

Water:
- it dissolves stuff well EX: anyt polar will dissolve
- water forms hydrogen bonds with anything polar and pulls it apart

What is the xylem in plants

Xylem:
- a thin narrow tube that transports water and the nutrients in the water from the roots of the plant to the leaves
- This is due to capillary action: the ability of water to flow against gravity in a narrow space + the co/adhesion of water
- water sticks to the plant and also to other water molecules

Define cohesion, adhesion, and surface tension

Cohesion:
- attraction between the same kind of molecules

Adhesion:
- Attraction between different kinds of molecules

Surface tension:
- property allowing liquid to resist external forces

Define buoyancy, viscosity, thermal conductivity, and specific heat capacity with examples in nature

Physical properties of water:

Buoyancy:
- defined as the upward force exerted by a fluid on something in the fluid
- since liquid water is less dense than air, aquatic animals have more buoyancy in water and float easier
- animal fat gives the animal more buoyancy

Viscosity:
- defined as a measure of a fluid’s resistance to flow
- Since water has a higher viscosity than air, many animals have a streamlined body to move more smoothly through the water

Thermal conductivity:
- the rate at which heat passes through the material and will vary based on the collision of particles
- since water has a higher TC than air, animals in water lose heat faster
- animals have adapted to the rapid heat loss in water such as no dorsal fin

Specific heat capacity:
- is defined as the energy required to raise the temp of 1g of a substance by 1 Celsius
- water has a high heat cap of 4.186 j/g Celsius cause it has lots of hydrogen bonds to break
- animal cells are resistant to temp change so it maintain body temp
- metals can change temp quickly causing low heat cap cause they’re better conductors
- large bodies of water have high heat caps which is ideal for organisms that thrive in a range of temp

Discuss why ice was not present during pre-biotic earth + how water came to earth

Water:
- water as ice was not present because the temp was too high + any gas water were moved by solar winds
- water formed outside of solar system due to low temp
- earth’s water came from asteroids or carbonaceous chondrites from the “Late Heavy Bombardment”

What is the Goldilocks zone

Zone:
- planets are in a goldilocks zone where their orbit around stars allows for liquid water
- not too far from the sun and not too close
- earth’s temp is suitable for water cycle and for life

Describe the composition of DNA and RNA + how does nucleotides form

Comp:
- made of a deoxyribose (sugar) + nitrogenous bases and a phosphate group
- same for RNA except the sugar is ribose
- These are called nucleotides which are formed via condensation reactions

Outline differences between RNA and DNA

RNA:
- Single Stranded
- Has AUCG bases (AU + CG)
- has ribose sugar
- has an extra oxygen off 3 prime carbon
- relatively shorter

DNA:
- double-stranded or double helix
- is anti-parallel
- has ATCG bases (CG + AT)

What is the composition of a nucleotide + the comp of pentose sugars

Nucleotide:
- Is defined as an organic molecule or pentose sugar, nitrogenous bases, and a phosphate group
- pentose sugars have 5 carbon called primes
- the fifth carbon is not on the molecule but instead bonded to a phosphate group.
- oxygen takes the last spot

Define transcrption and translation

Transcription:
- DNA code is transcribed to mRNA code
- in nucleus

Translation:
- mRNA code is translated by ribosomes into a polypeptide sequence
- in ribosomes

How many chromosomes does human usually have

Chromo:
- 23 pairs

Define genes

sequences of nitrogenous bases which is a code for specific protein and determines amino acid sequence

What is a codon

3 nitrogenous bases

What are purines and pyrimidines

Purines:
- bases w 2-ringed structure EX: A and G

Pyrimidines:
- bases w 1 ring structure EX: U, T, and C

pyrimidines bond with purines

What is the tetranucleotide hypothesis and how was it debunked

Tetranucleotide Hypothesis:
- hypothesis that DNA had 4 strands and the DNA sequence is always TACG
a
- this was disproved by looking at the % of bases
- since the % of bases within the sample is diff, then it can’t always be TACG
- the conc of A and T are relatively equal + vice versa

What is Chargaff’s rule

Chargaff:
- % of A = T and C=G are the same
- A bonds with T and creates 2 hydrogen bonds
- C and G bonds and creates 3 hydrogen bonds

Describe the discovery of DNA

DIscovery:
- Watson and crick figured out the bases unions
- Rosalind Franklin generated DNA crystal and shot x rays through which produced a double helix

What are nucleosomes

Nucleosome:
- is defined as negatively charge DNA wrapped twice around a core of 8 histones proteins + another linker histone protein to hold nucleosome tgt

Explain the Hershey-Chase experiment

Experiment:
- The purpose of this experiment is to find out whether protein or DNA was the genetic information
- They let bacteriophages (which are viruses that infect bacteria with their genetic info) infect e coli
- This particular bacteriophage had a DNA core and a protein coat
- They labelled one w radioactive phosphorus and one w radioactive Sulfer because DNA contains phosphors and vice-versa
- The bacteriophage infected the bacteria
- They put the bacteria into a centrifuge to separate the heavy bacteria to come as a pellet
- fhey checked if it had radioactivity and found it in the dna sample or phosphorus radioactive
- This revealed that the bacteriophage injected DNA inside thus DNA must be the genetic information.
Note: the substance in the centrifuge that isn’t the pellet is called the supernatant

Outline the composition of an amino acid

Amino acid:
- its made of an amine group, a central carbon or alpha carbon, and a carboxyl group + a side chain

What is the importance of the R side chain

R Side Chain:
- R side chain determines the chemical characteristics of amino acids of an assembled polypeptide
- can be categorized as hydrophilic or hydrophobic

How many types of amino acids are there

20 and all living organims share it

How do polypeptides form+ how are they bonded + How are they classified

Form:
- Amino acids undergo condensation reactions to form polypeptides in the ribosome during translation
- they are bonded with peptide bonds which is a type of covalent bond

Classified:
- 1 = peptide, 2 = dipeptide, 20 = Oligopeptide, 20+ = polypeptide or a protein

What is the difference between essential and nonessential amino acids + what are complete proteins

Essential:
- are amino acids that need to be obtained via diet
Non-essential:
- are amino acids that the body are able to synthesize

Complete:
- complete proteins contain 9 essential amino acids EX: meat

Define denaturation + causes of denaturation

Denaturation:
- is defined as a conformational change in the shape of a molecule such as protein that results in loss of function
- when heated, the molecules vibrate a lot thus causing for the hydrogen bonds to break and ionic bonds break

Causes:
- could be due to pH or temp change
- it breaks that hydrogen bonds

Describe the primary structure in protein folding

Primary:
- the primary structure simply establishes the sequence of amino acids
- they are formed via condensation reactions and bonded w peptide bonds
- Theres always a free amine group and a carboxyl group at the end as well

Describe the secondary structure

Secondary:
- the protein starts to fold
- its held tgt with hydrogen bonds between oxygen of carboxyl and the hydrogen of amino group
- they can either be folded into a alpha helix or a beta pletaed sheet

Describe the tertiary structure

Tertiary:
- further folding of proteins due to the R-group interactions
- interactions include covalnet, ionic, and hydrogen bonds forming
- an example of cov bond are disulfide bridges between cysteine
- in this stage, the hydrophobic amino acids will be in the globular proteins while the hydrophilic will be on the outside

Describe quaternary

Quaternary:
- different polypeptides come tgt and r group from diff polypeptides are keeping them tgt
- r group interactions are the same as tertiary

What are conjugated proteins + Non conjugated proteins

Conjugated:
- a conjugated protein is a protein attached to a non-polypeptide group which is called a prosthetic group EX: hemoglobin

Non Conjugated:
- non-conjugated proteins are composed of only polypeptides EX: insulin

Describe the structure of collagen and insulin + their uses

Collagen:
- is a fibrous protein composed of 3 polypeptide chains that are tightly coiled tgt in a triple helix structure
- main structural protein in connective tissue + provides structural support
- bonded together by disulfide bonds

Insulin:
- is a globular protein that is composed of two polypeptide chain that are inked by 2 disulfide bridges
- helps with blood regulation as it causes the liver to remove glucose from blood
- bonded together w hydrogen bonds
Note: we can use cryogenic microscopy to observe protein structure

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Unit 2: Molecules Flashcards

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